A palletizer is an apparatus that receives and manipulates items, such as boxes, also called cases, and places the manipulated items on pallets in pre-determined positions and orientations in organized rows, layers and stacks to form a stable stack of boxes arranged on a pallet for shipping. Palletizers are often combined with stretch wrapping machines that are either a component of the palletizer assembly itself or a separate machine. In either case, the stretch wrapping machine overwraps the stack of cases that the palletizing machine has deposited on the pallet in order to form a highly stable load that is ready for shipping and which will remain stable throughout the shipping process.
There are innumerable devices for palletizing articles, but described in a very general sense all palletizers receive a sequence of items and manipulate those items to produce a palletized stack of them. As noted, typically, a completed stack of cases is shrink wrapped as part of the palletizing operation in order to finalize the stack for shipping.
Stated in very general terms, a typical palletizer receives a series of items from an infeed conveyer, organizes the items into one or more rows on a row build conveyer, organizes the rows into layers on a component such as a layer head, and generates a stack of layers on a pallet. Depending on the type of machine, complete rows of cases may be transferred to onto a pallet or a complete layer of items (i.e., multiple rows of items) may be assembled and transferred at once onto a pallet.
Efficient shipping of palletized items calls for efficient stacking of items on the pallet to minimize open space within the stack and to help insure the stability of the stack to prevent relative movement between items, and ultimately, to insure that the items in the stack arrive at their destination undamaged. Of course, boxes come in a variety of sizes and many boxes are rectangular with opposed parallel side panels and therefore have different width and length dimensions. A standard pallet is used widely throughout the shipping industry. By varying the orientation and/or pattern of boxes from layer to layer, a stable stack of items may be constructed upon a standard-sized pallet. Accordingly, a variety of “box patterns” have been established for stacking specific box sizes on standard pallets. By using an established box pattern for given rectangular boxes that are to be stacked on a standard pallet, the result is an efficient and stable stack of the boxes on the pallet that will perform well during shipping and handling. Modern palletizers are under the control of a microprocessor that controls all aspects of the palletizing operation. Among other things, the controller has pre-determined “build menus” that correspond to box patters and which are specific to specific box dimensions and pallet load specifications. During operation of the palletizer, the build menu determines how the palletizer orients and arranges the plural boxes so that the finalized stack on the pallet is optimally stable.
A common palletizing system comprises several components that work together to perform the palletizing operation. Boxes are initially placed on an infeed system that delivers the boxes to a row build system. Often the infeed system includes box turning equipment that orients individual boxes in the correct orientation relative to adjacent boxes for the specific box pattern that is being used. Rows are assembled on the row build system—each row is a set of plural boxes arranged according to the box pattern as set by the build menu. A row is transferred by one of a variety of methods from the row build system to a layer building station where plural rows are arranged into a layer. A stack is formed by depositing a first layer onto a pallet or slip sheet and subsequent layers are deposited atop the next adjacent lower layer. Layers are added until the stack is complete. Typically, the palletizing operations at the various stations run simultaneously to the extent possible to increase throughput efficiency. As would be expected, there are many variations of the equipment used to palletize, and the general themes of operation.
Regardless of the equipment that is being used, palletizing requires efficiency in design and operation of the device. Among other design and operational criteria, efficiency is often one of the most important considerations. In many applications, time is most critical and a palletizer that more quickly organizes an incoming series of items into a palletized stack of items represents an advantage by increasing throughput and thus greater production levels and economic efficiency.
That said, different operations have different requirements for palletizing equipment. A high speed, high throughput palletizer might be appropriate for a high volume manufacturer but a lower speed system would be just as appropriate for a lower volume manufacturer. As would be expected, the higher speed palletizing systems tend to be more expensive than the lower speed system. Therefore, there is a need in the marketplace for many different palletizing systems that meet the variety of needs of the consumers of these systems.
It will be appreciated that mishandling of boxes in the palletizing process should be minimized as part of an efficient operation and that a palletizing system must be designed to avoid delivery of boxes to the palletizer in an incorrect orientation. For example, a box that is delivered to a palletizer in the incorrect orientation for the specific box pattern that is being used will cause formation of a defective layer. This results in shut down, or at least significant slowdown of the entire palletizing sequence and operator intervention is often required in order to correct the orientation of the mis-oriented box. Unfortunately, delivery of such “out of bounds” boxes—that is, boxes that are either in the incorrect orientation or which are otherwise improperly placed—to palletizing systems continues to be a significant problem and is the cause of much slowdown in palletizing operations. Moreover, any time operator intervention is required to correct out of bounds situations presents a safety concern for workers.
There is a need therefore for a palletizing system that insures delivery of boxes to the equipment in the correct orientation and spacing for whatever box pattern is being used. At the same time, there is a need for a palletizing system that meets the economies of the consumer's specific needs.
The present invention comprises systems that address the shortcomings of prior systems and is directed to a case manipulator that accurately and precisely positions cases on a row build system according to a pre-determined build menu. The case manipulator according to the present invention is capable of receiving cases from an infeed conveyer, manipulating individual cases when received from the infeed conveyer, transferring the manipulated cases to a row accumulator platform in a desired and pre-determined orientation and positioned on the accumulator platform to a desired and pre-determined location. The manipulation of individual cases, or groups of cases, is continued in a sequential operation until a complete row is formed on the accumulator platform according to the build menu. The invention allows the palletizer to have the next case in a row transferred from the infeed conveyer to the row-build staging area while the case manipulator is operating on an already-delivered case. These and other benefits are described herein.